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FA-67951 / Traffic signal timing plans / Open access

Pedestrian walk and clearance timing: walk is extended by comparing walk alone to total crossing time · case 01

Pedestrian walk and clearance timing returns a wrong result when walk is extended by comparing walk alone to total crossing time.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The condition ignores FDW, so walk gets extended (even shortened) whenever min walk is below the whole crossing time.

THE FAILURE

The condition ignores FDW, so walk gets extended (even shortened) whenever min walk is below the whole crossing time.

Unsuccessful approach: Comparing FDW alone ignores the walk interval that already counts toward the total.

Case contract

Input {crossing_ft, walk_speed_tenths (ft/s*10), min_walk, yellow_tenths, red_tenths, min_green, ped_call, split}. FDW = ceil(crossing*10/speed). Walk starts at min_walk and is extended so that walk + FDW >= ceil((crossing + 6)/3.0) (pushbutton-to-far-curb check at 3.0 ft/s). FDW may overlap yellow and all-red, so with a ped call the vehicle green is max(min_green, ceil(walk + FDW - (yellow+red))). Without a call green = min_green. fits is green + yellow + red <= split. Return {walk, fdw, green, fits}.

Why this case matters

Signal timing arithmetic is exact and integer or rational; a wrong rule silently produces unsafe or inefficient timing plans.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
import math
N = 1
observations = []
def solve(x):
    sp = x['walk_speed_tenths']
    fdw = -(-x['crossing_ft'] * 10 // sp)
    walk = x['min_walk']
    total = -(-(x['crossing_ft'] + 6) * 10 // 30)
    if walk < total:
        walk = total - fdw
    yr = Fraction(x['yellow_tenths'] + x['red_tenths'], 10)
    g = x['min_green']
    if x['ped_call']:
        need = walk + fdw - yr
        g = max(g, math.ceil(need))
    return {'walk': walk, 'fdw': fdw, 'green': g, 'fits': g + yr <= x['split']}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 81, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 45, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 34}, {'walk': 5, 'fdw': 24, 'green': 23, 'fits': True}), ({'crossing_ft': 93, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 10, 'ped_call': True, 'split': 27}, {'walk': 7, 'fdw': 27, 'green': 30, 'fits': False}), ({'crossing_ft': 80, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 45, 'red_tenths': 10, 'min_green': 8, 'ped_call': True, 'split': 38}, {'walk': 9, 'fdw': 20, 'green': 24, 'fits': True}), ({'crossing_ft': 32, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 10, 'ped_call': False, 'split': 27}, {'walk': 7, 'fdw': 10, 'green': 10, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 58, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 20, 'min_green': 10, 'ped_call': True, 'split': 24}, {'walk': 7, 'fdw': 15, 'green': 17, 'fits': True})], [({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 86, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': False, 'split': 18}, {'walk': 6, 'fdw': 25, 'green': 5, 'fits': True}), ({'crossing_ft': 33, 'walk_speed_tenths': 30, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 5, 'ped_call': True, 'split': 42}, {'walk': 7, 'fdw': 11, 'green': 13, 'fits': True}), ({'crossing_ft': 91, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 10, 'ped_call': True, 'split': 17}, {'walk': 7, 'fdw': 26, 'green': 29, 'fits': False}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 35, 'walk_speed_tenths': 40, 'min_walk': 5, 'yellow_tenths': 30, 'red_tenths': 20, 'min_green': 15, 'ped_call': True, 'split': 43}, {'walk': 5, 'fdw': 9, 'green': 15, 'fits': True}), ({'crossing_ft': 82, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 20, 'min_green': 10, 'ped_call': True, 'split': 26}, {'walk': 7, 'fdw': 24, 'green': 26, 'fits': False}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True})], [({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 26, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 8, 'ped_call': True, 'split': 44}, {'walk': 4, 'fdw': 7, 'green': 8, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 24, 'walk_speed_tenths': 30, 'min_walk': 7, 'yellow_tenths': 45, 'red_tenths': 20, 'min_green': 5, 'ped_call': False, 'split': 34}, {'walk': 7, 'fdw': 8, 'green': 5, 'fits': True}), ({'crossing_ft': 87, 'walk_speed_tenths': 40, 'min_walk': 5, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 15, 'ped_call': True, 'split': 43}, {'walk': 9, 'fdw': 22, 'green': 26, 'fits': True}), ({'crossing_ft': 103, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 45, 'red_tenths': 20, 'min_green': 10, 'ped_call': True, 'split': 18}, {'walk': 7, 'fdw': 30, 'green': 31, 'fits': False}), ({'crossing_ft': 64, 'walk_speed_tenths': 30, 'min_walk': 5, 'yellow_tenths': 40, 'red_tenths': 15, 'min_green': 5, 'ped_call': False, 'split': 26}, {'walk': 5, 'fdw': 22, 'green': 5, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True})], [({'crossing_ft': 73, 'walk_speed_tenths': 35, 'min_walk': 5, 'yellow_tenths': 35, 'red_tenths': 20, 'min_green': 10, 'ped_call': True, 'split': 26}, {'walk': 6, 'fdw': 21, 'green': 22, 'fits': False}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 108, 'walk_speed_tenths': 35, 'min_walk': 5, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 35}, {'walk': 7, 'fdw': 31, 'green': 32, 'fits': False}), ({'crossing_ft': 87, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 30, 'red_tenths': 20, 'min_green': 10, 'ped_call': True, 'split': 20}, {'walk': 9, 'fdw': 22, 'green': 26, 'fits': False}), ({'crossing_ft': 72, 'walk_speed_tenths': 30, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 5, 'ped_call': False, 'split': 15}, {'walk': 4, 'fdw': 24, 'green': 5, 'fits': True}), ({'crossing_ft': 44, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 45, 'red_tenths': 15, 'min_green': 8, 'ped_call': False, 'split': 32}, {'walk': 7, 'fdw': 13, 'green': 8, 'fits': True}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True})], [({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 99, 'walk_speed_tenths': 35, 'min_walk': 5, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 15, 'ped_call': True, 'split': 20}, {'walk': 6, 'fdw': 29, 'green': 30, 'fits': False}), ({'crossing_ft': 51, 'walk_speed_tenths': 35, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 10, 'min_green': 10, 'ped_call': False, 'split': 40}, {'walk': 10, 'fdw': 15, 'green': 10, 'fits': True}), ({'crossing_ft': 77, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 15, 'ped_call': True, 'split': 18}, {'walk': 8, 'fdw': 20, 'green': 22, 'fits': False}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 72, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 45, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 23}, {'walk': 8, 'fdw': 18, 'green': 20, 'fits': False}), ({'crossing_ft': 29, 'walk_speed_tenths': 35, 'min_walk': 10, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 5, 'ped_call': True, 'split': 32}, {'walk': 10, 'fdw': 9, 'green': 14, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True})]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('timing oracle' + ' %d' % i, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
timing oracle 0{'fdw': 26, 'fits': True, 'green': 27, 'walk': 6}{'fdw': 26, 'fits': True, 'green': 27, 'walk': 6}Passed
timing oracle 1{'fdw': 20, 'fits': True, 'green': 20, 'walk': 6}{'fdw': 20, 'fits': True, 'green': 21, 'walk': 7}Failed
timing oracle 2{'fdw': 24, 'fits': True, 'green': 23, 'walk': 5}{'fdw': 24, 'fits': True, 'green': 23, 'walk': 5}Passed
timing oracle 3{'fdw': 27, 'fits': False, 'green': 29, 'walk': 6}{'fdw': 27, 'fits': False, 'green': 30, 'walk': 7}Failed
timing oracle 4{'fdw': 20, 'fits': True, 'green': 24, 'walk': 9}{'fdw': 20, 'fits': True, 'green': 24, 'walk': 9}Passed
timing oracle 5{'fdw': 10, 'fits': True, 'green': 10, 'walk': 3}{'fdw': 10, 'fits': True, 'green': 10, 'walk': 7}Failed
timing oracle 6{'fdw': 9, 'fits': True, 'green': 8, 'walk': 5}{'fdw': 9, 'fits': True, 'green': 8, 'walk': 7}Failed
timing oracle 7{'fdw': 15, 'fits': True, 'green': 17, 'walk': 7}{'fdw': 15, 'fits': True, 'green': 17, 'walk': 7}Passed

SHA-256 / d3ef1df9d3c7fc972f87b0d409463e99f865f4f819b39990ebce29c5ba032cba

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
import math
N = 1
observations = []
def solve(x):
    sp = x['walk_speed_tenths']
    fdw = -(-x['crossing_ft'] * 10 // sp)
    walk = x['min_walk']
    total = -(-(x['crossing_ft'] + 6) * 10 // 30)
    if fdw < total:
        walk = total - fdw
    yr = Fraction(x['yellow_tenths'] + x['red_tenths'], 10)
    g = x['min_green']
    if x['ped_call']:
        need = walk + fdw - yr
        g = max(g, math.ceil(need))
    return {'walk': walk, 'fdw': fdw, 'green': g, 'fits': g + yr <= x['split']}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 81, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 45, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 34}, {'walk': 5, 'fdw': 24, 'green': 23, 'fits': True}), ({'crossing_ft': 93, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 10, 'ped_call': True, 'split': 27}, {'walk': 7, 'fdw': 27, 'green': 30, 'fits': False}), ({'crossing_ft': 80, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 45, 'red_tenths': 10, 'min_green': 8, 'ped_call': True, 'split': 38}, {'walk': 9, 'fdw': 20, 'green': 24, 'fits': True}), ({'crossing_ft': 32, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 10, 'ped_call': False, 'split': 27}, {'walk': 7, 'fdw': 10, 'green': 10, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 58, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 20, 'min_green': 10, 'ped_call': True, 'split': 24}, {'walk': 7, 'fdw': 15, 'green': 17, 'fits': True})], [({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 86, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': False, 'split': 18}, {'walk': 6, 'fdw': 25, 'green': 5, 'fits': True}), ({'crossing_ft': 33, 'walk_speed_tenths': 30, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 5, 'ped_call': True, 'split': 42}, {'walk': 7, 'fdw': 11, 'green': 13, 'fits': True}), ({'crossing_ft': 91, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 10, 'ped_call': True, 'split': 17}, {'walk': 7, 'fdw': 26, 'green': 29, 'fits': False}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 35, 'walk_speed_tenths': 40, 'min_walk': 5, 'yellow_tenths': 30, 'red_tenths': 20, 'min_green': 15, 'ped_call': True, 'split': 43}, {'walk': 5, 'fdw': 9, 'green': 15, 'fits': True}), ({'crossing_ft': 82, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 20, 'min_green': 10, 'ped_call': True, 'split': 26}, {'walk': 7, 'fdw': 24, 'green': 26, 'fits': False}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True})], [({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 26, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 8, 'ped_call': True, 'split': 44}, {'walk': 4, 'fdw': 7, 'green': 8, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 24, 'walk_speed_tenths': 30, 'min_walk': 7, 'yellow_tenths': 45, 'red_tenths': 20, 'min_green': 5, 'ped_call': False, 'split': 34}, {'walk': 7, 'fdw': 8, 'green': 5, 'fits': True}), ({'crossing_ft': 87, 'walk_speed_tenths': 40, 'min_walk': 5, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 15, 'ped_call': True, 'split': 43}, {'walk': 9, 'fdw': 22, 'green': 26, 'fits': True}), ({'crossing_ft': 103, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 45, 'red_tenths': 20, 'min_green': 10, 'ped_call': True, 'split': 18}, {'walk': 7, 'fdw': 30, 'green': 31, 'fits': False}), ({'crossing_ft': 64, 'walk_speed_tenths': 30, 'min_walk': 5, 'yellow_tenths': 40, 'red_tenths': 15, 'min_green': 5, 'ped_call': False, 'split': 26}, {'walk': 5, 'fdw': 22, 'green': 5, 'fits': True}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True})], [({'crossing_ft': 73, 'walk_speed_tenths': 35, 'min_walk': 5, 'yellow_tenths': 35, 'red_tenths': 20, 'min_green': 10, 'ped_call': True, 'split': 26}, {'walk': 6, 'fdw': 21, 'green': 22, 'fits': False}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True}), ({'crossing_ft': 108, 'walk_speed_tenths': 35, 'min_walk': 5, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 35}, {'walk': 7, 'fdw': 31, 'green': 32, 'fits': False}), ({'crossing_ft': 87, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 30, 'red_tenths': 20, 'min_green': 10, 'ped_call': True, 'split': 20}, {'walk': 9, 'fdw': 22, 'green': 26, 'fits': False}), ({'crossing_ft': 72, 'walk_speed_tenths': 30, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 5, 'ped_call': False, 'split': 15}, {'walk': 4, 'fdw': 24, 'green': 5, 'fits': True}), ({'crossing_ft': 44, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 45, 'red_tenths': 15, 'min_green': 8, 'ped_call': False, 'split': 32}, {'walk': 7, 'fdw': 13, 'green': 8, 'fits': True}), ({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True})], [({'crossing_ft': 90, 'walk_speed_tenths': 35, 'min_walk': 4, 'yellow_tenths': 35, 'red_tenths': 15, 'min_green': 10, 'ped_call': True, 'split': 35}, {'walk': 6, 'fdw': 26, 'green': 27, 'fits': True}), ({'crossing_ft': 99, 'walk_speed_tenths': 35, 'min_walk': 5, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 15, 'ped_call': True, 'split': 20}, {'walk': 6, 'fdw': 29, 'green': 30, 'fits': False}), ({'crossing_ft': 51, 'walk_speed_tenths': 35, 'min_walk': 10, 'yellow_tenths': 35, 'red_tenths': 10, 'min_green': 10, 'ped_call': False, 'split': 40}, {'walk': 10, 'fdw': 15, 'green': 10, 'fits': True}), ({'crossing_ft': 77, 'walk_speed_tenths': 40, 'min_walk': 4, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 15, 'ped_call': True, 'split': 18}, {'walk': 8, 'fdw': 20, 'green': 22, 'fits': False}), ({'crossing_ft': 36, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 30, 'red_tenths': 10, 'min_green': 8, 'ped_call': False, 'split': 12}, {'walk': 7, 'fdw': 9, 'green': 8, 'fits': True}), ({'crossing_ft': 72, 'walk_speed_tenths': 40, 'min_walk': 7, 'yellow_tenths': 45, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 23}, {'walk': 8, 'fdw': 18, 'green': 20, 'fits': False}), ({'crossing_ft': 29, 'walk_speed_tenths': 35, 'min_walk': 10, 'yellow_tenths': 40, 'red_tenths': 10, 'min_green': 5, 'ped_call': True, 'split': 32}, {'walk': 10, 'fdw': 9, 'green': 14, 'fits': True}), ({'crossing_ft': 70, 'walk_speed_tenths': 35, 'min_walk': 7, 'yellow_tenths': 40, 'red_tenths': 20, 'min_green': 5, 'ped_call': True, 'split': 30}, {'walk': 7, 'fdw': 20, 'green': 21, 'fits': True})]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('timing oracle' + ' %d' % i, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
timing oracle 0{'fdw': 26, 'fits': True, 'green': 27, 'walk': 6}{'fdw': 26, 'fits': True, 'green': 27, 'walk': 6}Passed
timing oracle 1{'fdw': 20, 'fits': True, 'green': 20, 'walk': 6}{'fdw': 20, 'fits': True, 'green': 21, 'walk': 7}Failed
timing oracle 2{'fdw': 24, 'fits': True, 'green': 23, 'walk': 5}{'fdw': 24, 'fits': True, 'green': 23, 'walk': 5}Passed
timing oracle 3{'fdw': 27, 'fits': False, 'green': 29, 'walk': 6}{'fdw': 27, 'fits': False, 'green': 30, 'walk': 7}Failed
timing oracle 4{'fdw': 20, 'fits': True, 'green': 24, 'walk': 9}{'fdw': 20, 'fits': True, 'green': 24, 'walk': 9}Passed
timing oracle 5{'fdw': 10, 'fits': True, 'green': 10, 'walk': 3}{'fdw': 10, 'fits': True, 'green': 10, 'walk': 7}Failed
timing oracle 6{'fdw': 9, 'fits': True, 'green': 8, 'walk': 5}{'fdw': 9, 'fits': True, 'green': 8, 'walk': 7}Failed
timing oracle 7{'fdw': 15, 'fits': True, 'green': 17, 'walk': 7}{'fdw': 15, 'fits': True, 'green': 17, 'walk': 7}Passed

SHA-256 / 1f96a1d271e6419eb8ca68599cbae461cf6f52828d78cbef3e4045d1fd134ce3

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

A deterministic, bounded toy model with a stipulated contract; it makes no claim of conformance to any agency manual or standard. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:47:57.677786+00:00.

Case digest / 8e73be097f467ffad551949b89eae8987c2555e17c34a50de8f558ea435093b4